To this end, we generated constitutive knockout (KO) cell lines for EXO1 in diploid chronic myelogenous leukaemia eHAP and in cervical adenocarcinoma HeLa Kyoto cells harbouring an integrated inducible Cas9 (Fig. 1a, Supplementary Fig. 1a). The gene discussed is EXO1; the disease is myeloid leukemia.